Status of the Cabibbio - Radicati sum rule and a new test of vector meson dominance

Abstract

Using finite energy sum rules the high energy contribution to the Cabibbo-Radicati sum rule is calculated and shown to be of the proper magnetude and sign, so that this sum rule is exactly satisfied. In addition the coupling of the ϱ Regge trajectory to two charged photons is calculated and found to be in agreement with the predictions of vector meson dominance and universality for the Reggeized ϱ vertex, within the expected accuracy.